Who in their right mind would say, "Just Four-Twenty and Nineteen days left to my wedding"? Unless you are a mathematician or French! You see, some clever French decided that giving names to all numbers is such a waste of time. Numbers till sixty are sufficient. All numbers after that can be derived from existing numbers. So, 70 became soixante-dix (60 & 10); 72 became soixante-douze (60 & 12); 80 became quatre-vingt (four-twenty); and 99 became, your guessed it, quatre-vingt-dix-neuf (four-twenty & nineteen).
I wonder if any study has been conducted to determine if French children are good at arithmetic.